Polarizers have been used to reduce glare and the light intensity in eyeglasses for some time. For example, U.S. Pat. No. 2,005,426 issued to Land in 1935 teaches adjustable polarized eyeglasses with two polarizer elements for each eye. The rear elements are rotatable so that the intensity of transmitted light can be adjusted.
U.S. Pat. No. 2,813,459 issued to Archambault in 1957 teaches adjustable polarized eyeglasses with two polarizer elements for each eye, wherein the rear elements are coupled so that the light intensity transmitted to both eyes is the same.
Further improvements are taught in U.S. Pat. No. 3,944,346 (Shindler), U.S. Pat. No. 4,119,369 (Eloranta et al), U.S. Pat. No. 4,149,780 (Young), U.S. Pat. No. 4,386,832 (Nannini), U.S. Pat. No. 4,943,152 (Whelen), and U.S. Pat. No. 5,355,183 (Andea).